The amount of information available on the World Wide Web (the internet) and other networks is enormous and rapidly expanding. Searching and locating specific aspects of this information can be quite challenging.
Search engines seek and retrieve network information that relates to a specific request or query. An internet search engine, for example, uses a web crawler (or web spider) to search the internet to retrieve, copy, index, and store web pages and related information. Typically, the contents of each web page are analyzed to determine how the page should be indexed. Words may be extracted from the titles, headings, or special fields known as meta tags. Data concerning each page is then stored in an index database. During a search, a user enters a query, such as key words. The search engine compares the query with the index database and provides a listing of most relevant web pages according to the key words.
One goal of a search engine is to provide the user with the most relevant search results based on the initial query. The task of providing relevant search results is quite complex since thousands to millions of web pages may contain the particular key words entered in the query. In order to cull through the resulting web pages, many search engines employ methods to rank the search results so the user is presented with the most relevant results first.
Search engines utilize various schemes (such as ranking algorithms) to rank the search results. Accurately ranking a web page is difficult since the importance of a web page to a user is inherently subjective. To increase ranking accuracy, some search engines use page ranking to assign weights or scores to web pages. For example, web pages can be ranked accordingly to criteria other than content, such as the popularity of a page, the number of citations or backlinks to a page, or the quality of a page.
Ranking web pages according to popularity or backlinks to a page does not necessarily ensure that the most relevant pages are being presented to the user. A web page, for example, may be popular with large numbers of internet users. This popular web page, though, may not be the most authoritative or relevant site to the search query.